2019/03/02 by Max Hirschberger, Hirschberger, Max, Peter Czajka +7
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Multiferroics and related materials #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.1903.00595
openalex publication_date 2019/03/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this letter, we report the gigantic thermal Hall effect κxy in the low-field correlated-paramagnetic state of the frustrated pyrochlore Yb2Ti2O7. We observed a record magnitude for the thermal Hall angle in an insulator, |κxy|/κxx∼ 2 %. The signal onsets at T∼ 3 K and is severely weakened around the transition to canted ferromagnetic order at TCFM=0.275 K. Besides the large κxy>0 of the fluctuating regime, a sign change towards negative κxy occurs at the lowest temperatures and in moderate field, where sharp magnon excitations appear in the inelastic neutron scattering spectra. We analyze the magnon-Hall signal and its suppression with field semi-quantitatively. A contribution of phonon skew scattering to κxy is ruled out by a comparison of κxx for Tb-, Yb-, and Y-based rare earth pyrochlore titanates. These results represent the first report of non-vanishing κxy measured in a dilution refrigerator (T < 0.29 K).